The present invention relates to a jet engine thrust reverser system and, more particularly, to a thrust reverser system that includes actuators having an integrated locking mechanism.
When jet-powered aircraft land, the landing gear brakes and imposed aerodynamic drag loads (e.g., flaps, spoilers, etc.) of the aircraft may not be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the stopping power of the aircraft. When deployed, thrust reversers redirect the rearward thrust of the jet engine to a forward direction to decelerate the aircraft. Because the jet thrust is directed forward, the jet thrust also slows down the aircraft upon landing.
Various thrust reverser designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Thrust reverser designs used most prominently with turbofan jet engines fall into three general categories: (1) cascade-type thrust reversers; (2) target-type thrust reversers; and (3) pivot door thrust reversers. Each of these designs employs a different type of moveable thrust reverser component to change the direction of the jet thrust.
Cascade-type thrust reversers are normally used on high-bypass ratio jet engines. This type of thrust reverser is located on the circumference of the engine""s midsection and, when deployed, exposes and redirects air flow through a plurality of cascade vanes. The moveable thrust reverser components in the cascade design includes several translating sleeves or cowls (xe2x80x9ctranscowlsxe2x80x9d) that are deployed to expose the cascade vanes.
Target-type reversers, also referred to as clamshell reversers, are typically used with low-bypass ratio jet engines. Target-type thrust reversers use two doors as the moveable thrust reverser components to block the entire jet thrust coming from the rear of the engine. These doors are mounted on the aft portion of the engine and may form the rear part of the engine nacelle.
Pivot door thrust reversers may utilize four doors on the engine nacelle as the moveable thrust reverser components. In the deployed position, these doors extend outwardly from the nacelle to redirect the jet thrust.
The primary use of thrust reversers is, as noted above, to enhance the stopping power of the aircraft, thereby shortening the stopping distance during landing. Hence, thrust reversers are primarily deployed during the landing process to slow the aircraft. Thereafter, when the thrust reversers are no longer needed, they are returned to their original, or stowed, position and are locked.
The thrust reversers in each of the above-described designs are moved between the stowed and deployed positions by means of actuators. For flight-safety reasons, it is required that the one or more of the actuators used to move the thrust reversers include a locking function to prevent unintended thrust reverser movement. Current thrust reverser systems incorporate the locking devices as separate units that may attach to one or more components of the thrust reverser system. For example, U.S. Pat. No. 4,586,329 (the ""329 patent) discloses a locking device that is coupled to the gear shafts that couple the thrust reverser system actuators together. In another example, U.S. Pat. No. 5,448,884 (the ""884 patent) discloses a locking device that is attached to a thrust reverser actuator.
The locking devices disclosed in the ""329 patent and the ""884 patent are known to be complex and heavy, and are known to increase system inertia and size envelope. Hence, there is a need for a thrust reverser actuator locking device that improves upon one or more of these drawbacks.
The present invention relates to a system for moving thrust reversers that includes a plurality of actuators each having an integrated locking mechanism that prevents unintended actuator movement, and thus unintended thrust reverser movement.
In one aspect of the present invention, and by way of example only, a system for moving a thrust reverser, includes at least one power source, at least two synchronization mechanisms, and at least two actuators each coupled to at least one of the synchronization mechanisms. At least one of the actuators includes a housing assembly, a drive shaft, an actuator, and a lock. The housing assembly has a first opening, a second opening, a third opening, and a first inside surface defining a first chamber extending along a first axis between the first and second openings, the third opening being located between the first and second openings. The drive shaft is rotationally mounted between the openings within the chamber and in general alignment with the first axis, and has a gear portion, a lock portion and a first end adapted to couple to at least one of the synchronization mechanisms, the gear and lock portions are located within the chamber. The actuator extends from the third opening of the housing along a second axis that is perpendicular to the first axis, and has a drive gear mounted to engage the gear portion of the drive shaft. The lock is movably mounted within the chamber in an opposite, generally opposed position to the actuator, and has at least a side surface and a bottom surface and is selectively operable to move in a plane aligned with the second axis between at least a first position and a second position. The lock portion of the drive shaft has at least one protrusion extending radially outwardly, and each protrusion has a stop surface positioned to engage the lock side surface when the lock is in the first position to prevent the rotation of the drive shaft.
In another exemplary aspect of the present invention, a thrust reverser actuator with an integrated lock for use in a system having at least one synchronization mechanism for moving a thrust reverser between deployed and stowed positions includes a housing assembly, a drive shaft, an actuator, and a lock. The housing assembly has a first opening, a second opening, a third opening, and a first inside surface defining a first chamber extending along a first axis between the first and second openings, the third opening being located between the first and second openings. The drive shaft is rotationally mounted between the openings within the chamber and in general alignment with the first axis, and has a gear portion, a lock portion and a first end adapted to couple to at least one of the synchronization mechanisms, the gear and lock portions are located within the chamber. The actuator extends from the third opening of the housing along a second axis that is perpendicular to the first axis, and has a drive gear mounted to engage the gear portion of the drive shaft. The lock is movably mounted within the chamber in an opposite, generally opposed position to the actuator, and has at least a side surface and a bottom surface and is selectively operable to move in a plane aligned with the second axis between at least a first position and a second position. The lock portion of the drive shaft has at least one protrusion extending radially outwardly, and each protrusion has a stop surface positioned to engage the lock side surface when the lock is in the first position to prevent the rotation of the drive shaft.
Other independent features and advantages of the preferred sensor will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.